Billing demand recorder

ABSTRACT

A recording instrument, such as an electrical power meter, controls the actuation of an electrical switch from one position to another at a rate which is a function of a measured quantity, such as kilowatt hours. The electrical switch controls the direction of current flow through a magnetic recording head so that information representing the measured quantity can be placed on a recording medium. A constant current power supply is provided to insure consistency of information placed on the recording medium independently of line voltage changes, and light emitting diodes are included in series with the magnetic head to show the existence and the direction of current flow through the recording head. Latching flip-flops may also be included between the electrical switch and the recording head to prevent the recording of multiple marks due to switch bounce. Electrically actuated mechanical counters may also be used to record changes in switch position.

[ 1 June 27, 1972 [s41 BILLING DEMAND RECORDER [72] lnventors: James D.l-loeffel; Reinhold W. Kubach,

- both of Dayton, Ohio Dayton Electronic Products Company, Dayton, Ohio22 Filed: Jan. 20, 1971 211 Appl.No.: 108,088

[73] Assignee:

52 us. Cl. 346/17, 307/31 1, 340 253 346/14 MR, 346/74 M, 324 113 51Int. Cl .G01d13/00,Gllb 27/36 [58] Field olSearch ..346/l7, 14MR,33 M,74 M;

340/174.l G, 253 R, 253 S, 253 M, 248 R, 248 P, 203', 307/311, 132, 142;317/7; 324/113 [56] References Cited UNITED STATES PATENTS 3,125,7593/1964 Klein et al. ..346/74 M 3,148,329 9/1964 Lenehan ..324/l133,281,692 10/1966 Beroset ..324/133 X OTHER PUBLICATIONS InstructionManual For General Electric Type PDM- 70 Pulscript Demand Recorder(GEl-l- 2780) 3- 69.

Primary Examiner-Richard B. Wilkinson Assistant Examiner-J. W. HartaryAtt0rneyMarechal, Biebel, French & Bug

1 1 ABSTRACT A recording instrument, such as an electrical power meter,controls the actuation of an electrical switch from one position toanother at a rate which is a function of a nlcasurcd quantity, such askilowatt hours. The electrical switch controls the direction of currentflow through a magnetic recording head so that information representingthe measured quantity can be placed on a recording medium. A constantcurrent power supply is provided to insure consistency of informationplaced on the recording medium independently of line voltage changes,and light emitting diodes are included in series with the magnetic headto show the existence and the direction of current flow through therecording head. Latching flip-flops may also be included between theelectrical switch and the recording head to prevent the recording ofmultiple marks due to switch bounce. Electrically actuated mechanicalcounters may also be used to record changes in switch position.

7 Claims, 5 Drawing Figures PATENTEBJUM27 m2 SHEET 10F 2 RECORDERELECTRICAL POWER FIG-l SENDING UNIT l3 'GEAR BOX JAMES D. HOEFFEL8: BYREINHOLD W. KUBACH WM Mflq ATTORNEYS PATENTEBJUH 2 7 1072 SHEET 2 BF 2FIG-4 FIG-3 BACKGROUND OF THE INVENTION This invention relates to animproved recorder for use with instruments measuring a quantity withrespect to time. Such an instrument may measure kilowatt hours, KVA, orcurrent squared, all with respect to some time interval. The measuredparameter may be displayed by means of visible dials, and thisinformation may also be placed on a recording medium, such as magnetictape, as described in US. Pat. No. 3,148,329.

Typically, an electrical switch is actuated at a rate determined by themeasured quantity, and this switch controls the current through arecording head. Other switches may be employed to control the currentthrough a second recording head to indicate equal intervals of time toprovide a reference against which the parameter may be measured.

SUMMARY or THE INVENTION This invention relates to an improved recordingcircuit whereby the existence and direction of current flow through themagnetic recording heads may be determined visually and whereby therecording of multiple magnetic marks due to switch bounce is eliminated.

Specifically, this invention, responds to the operation of an electricalswitch, commonly called the pulse initiator, which is actuated by ameasuring instrument, with the rate at which the switch is actuated fromone position to another being determined by the quantity being measured.At least one magnetic recording head is arranged to record on a magnetictape a magnetic mark, the polarity of which is determined by theposition of the switch.

In a typical installation, the electrical switch may be actuated at aslow rate, i.e., less than 1 cycle per minute, and therefore it is oftendifficult to determine the proper operation of the recording circuit.For this reason, this invention includes a air of light emitting diodesconnected in inverse parallel relation with each other and in serieswith the recording head. These light emitting diodes permit the visualdetermination of the existence and direction of current flow at lowrecording current levels.

The invention contemplates the use of electrically actuated mechanicalcounters actuated by the electrical switch to record the measuredparameter simultaneously with the recording of magnetic marks on themagnetic tape.

This invention also includes the use of latching integrated circuitflip-flops between the electrical switch and the recording head andmechanical counter to prevent multiple pulses from being recorded due toswitch bounce thereby insuring the accuracy of the. recordedinformation.

Accordingly, it is an object of this invention to provide an improvedrecording instrument of the type described which includes light emittingdiodes to enable visual determination of the proper operation of therecording instrument including the existence and direction of currentflow through the magnetic recording head; to provide an improvedrecording device of the type described which includes latchingflip-flops between the electrical switch and the recording heads torevent multiple marks from being applied to the recording medium or toprevent multiple actuation of an electrically actuated mechanicalcounter due to switch bounce; and provide an improved recording deviceof the type described wherein light emitting diodes indicate the properfunctioning and operation of the pulse indicator incorporated in themeasuring instrument.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a typicalmeasuring instrument including means for actuating an electrical switchat a rate determined by the magnitude of a measured quantity;

FIG. 2 is a block electrical schematic diagram showing the generalelectrical arrangement of the components comprising this invention;

FIG. 3 is an electrical schematic diagram of one of the blocks of FIG.2, showing light emitting diodes connected in inverse parallel relationwith each other and in series with a magnetic recording head;

FIG. 4 is an electrical schematic diagram showing another embodiment ofthe invention; and

FIG. 5 is an electrical schematic diagram showing still anotherembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingswhich show the preferred embodiment of the invention, and particularlyto FIG. 1, a measuring instrument 10, such as a watt 'hour meter,includes a meter disc 11 which rotates at a rate determined by thequantity being measured. The meter disc 11 is connected to a rotatingshutter 12 through a gear box 13. The rotating shutter includes aplurality of apertures 15 which are spaced circumferentially and alignedwith a photocell 16. A second plurality of apertures 17 are aligned withphotocell 18. The light source 19 situated internally of the rotatingshutter 12 directs light through the apertures 15 and 17 to thephotocells.

The photocells 16 and 18 are connected to a sending unit 20 which, aswill be explained, includes a relay having at least one single-poledouble-throw switch element. The switch elements are connected by meansof a cable 21 to a recorder circuit 25 which includes a magnetic tape.The use of the rotating apertures 15 and the photoelectric cells 16 and18 permits effective electrical isolation between the measuringinstrument l0 and the recorder 25.

FIG. 2 is a block electrical diagram showing one embodiment of therecorder mechanism. The recorder mechanism includes a power supply 26having a transformer T1 connected to a conventional source of power, adiode bridge module AQl connected to the secondary of the transformer,Zener diode Z1, resistor R1 and filter capacitor C1. The power supplyhas two outputs, a 15 volt output on terminal 28 which is regulated bythe Zener diode Z1, ,and a 20 volt output on tenninal 29. The output onterminal 29 is connected to a constant current device 30 which includesZener Z2, transistor Q1 and resistors R2 and R3. The output of thisdevice on terminal 31 is used to supply a constant current to therecording devices located in the recording circuit shown generally inblocks 32-35. These recording devices are controlled bysingle-poledouble-throw switches 36-39 controlled by the measuring instrument l0.

Switches 36-38 are actuated from one position to another at a raterepresenting a measured parameter, such as kilowatt hours, currentsquared, volt amperes, etc., at a rate determined by the rotationalvelocity of the shutter 12 relative to the photocells 16 and 18. Switch39 may be controlled by a timer to provide a reference against which themeasured parameter can be decoded from the tape.

A tape and drive mechanism, not shown, are provided to record magneticmarks generated by magnetic recording heads in the recording devices32-35, with these marks usually being placed on the tape simultaneouslyin separate ing head. Thus, with the switch in the position shown,current will flow through resistors R4 and R5, LEDl the recording head40, and diode D2 to ground. Current also flows through resistor R6 anddiode D2 to ground, although this does not effect recording current.When the switch 36 is in the opposite direction, current throughresistor R6 will then flow in the opposite direction through therecording head 40, LED2 resistor R and diode D1 to ground. Thus, thisinvention employs nonretum to zero type recording where current flowseither in one direction or the other through a recording head.

The existence and the direction of current flowing through the recordinghead is indicated by a pair of light emitting diodes LED] and LED2.These are solid state devices which will provide illumination at the lowcurrent levels which are used in the recording heads. In the preferredembodiments of this invention, recording currents are maintained atbetween 2 and 4 milliamperes, and therefore in order to provide anindication of recording current, a device which responds to these lowcurrent levels must be used. In the preferred embodiment, light emittingdiodes Motorola type MLED60O are used. Thus,

' current in one direction through the recording head 40 is indicated bythe illumination of LEDl while current in the opposite direction isindicated by the illumination of LEDZ. If

neither of these light emitting diodes is illuminated, this indicates amalfunction of the pulse initiator or switch 36.

FIG. 4 represents another embodiment of the invention which alsoincludes light emitting diodes connected in inverse parallel relationwith each other and in series with a recording head. In this embodiment,a latching flip-flop circuit 45 is connected between switch 37 andrecording head 46. The latching flip-flop is a commercially availabledevice manufactured by Motorola, type MC672P. The latching flip-flopprevents any bounce between the contacts of the switches from beingreflected as current changes in the recording head thereby preventingmultiple marks from being applied to the recording medium. In thisembodiment, light emitting diodes LED3 and LED4 may also be employed toprovide a visual indication of the existence and direction of currentflow through the recording head.

The recording instrument may also be provided with electrically actuatedmechanical counters to record the number of changes in position of theelectrical switch. These mechanical recorders 5255, shown in FIG. 1, maybe electrically connected to each of the recording circuits. In FIG. 4,the mechanical recorder is connected to the output of the latchingflip-flop circuit and includes a pair of transistors Q2 and Q3 which actas switches to discharge energy stored on capacitors C2 and C3 into thecounter solenoid 57. The voltage on capacitors C2 and C3 is determinedby Zener diodes Z3 and Z4 and prevent an excessive voltage from beingapplied across the counter solenoid. Diode D5 provides a current pathfor the current induced in the solenoid when either transistor Q2 or 03is gated off. These Zener diodes limit the energy available to thecounter solenoids to prevent jamming. The counter circuit thus countseach change in position of the switch to provide a mechanical back upfor the magnetic tape on which is recorded the same information. Themechanical counter is optional and may be used with any of the circuitsof this invention.

FIG. 5 shows still another embodiment of the invention utilizing alatching flip-flop circuit 47 controlled by switch 38, however in thisembodiment, a constant voltage source is used to supply power to thelatching flip-flop at terminal 48 and the flip-flop circuit itselfsupplies current to light emitting diodes LEDS and LED6 and magneticrecording head 49. This circuit eliminates some of the components usedin the circuits of FIGS. 3 and 4, and employs both the light emittingdiodes to provide visual indication of the existence and direction ofcurrent flow through the recording head and a latching flip-flop toprevent the recording of multiple marks on a magnetic medium due toswitch bounce.

This invention therefore is an improved recording device for use withbilling recording instruments which allows the visual determination ofrecording currents of low magnitude, i.e., 2 to 4 milliamperes, andwhich insures accurate recording of the number of changes in switchposition both by magnetic and electromechanical means by preventing anyswitch bounce from creating multiple actuating signals.

Typical values of the components described in the specification anddrawings are as follows:

R1 C1 500 f R2 470 C2 260 f R3 3.3K C3 260 f R4 4.7Kv Dl-DS IN4005 R72.2K 01-03 2N5366 R8 2.2K LEDl-LED6 Motorola Type MLED6OO R9 1K QAl VAROType VIE-27 R11 IK R12 lK While the forms of apparatus herein describedconstitute preferred embodiments of the invention, it is to beunderstood that the invention is not limited to these precise forms ofapparatus, and that changes may be made therein without departing fromthe scope of the invention which is defined in the appended claims.

What is claimed is: 1. In a recording instrument including: anelectrical switch which can assume one of two positions; means foractuating said electrical switch between said positions at a rate whichis a function of a measured quantity;

at least one magnetic recording head for applying magnetic marks to arecording medium under the control of said electrical switch; and

means for supplying current to said magnetic recording head in adirection determined by the position of said electrical switch;

the improvement comprising:

a pair of light emitting diodes connected in inverse parallel relationwith each other and in series with each said magnetic recording head forindicating the existence of and the direction of current flow throughsaid recording head.

2. The recording instrument of claim 1 further including flip-flop meanselectrically connected between said electrical switch and said recordinghead for preventing multiple marks from being applied by said recordinghead to the recording medium due to switch bounce. 3. The recordinginstrument of claim 1 wherein a plurality of switches are provided tomeasure a corresponding plurality of measured quantities, wherein aplurality of magnetic recording heads are provided to apply magneticmarks to said recording medium, and wherein each of said switches isconnected to a corresponding flip-flop to control recording currentthrough corresponding said recording heads.

4. The recording instrument of claim 1 further including means forcounting the changes in position of said switch means independently ofthe recording of magnetic marks on said recording medium.

5. In a recording instrument including an electrical switch which canassume one of two positions; means for actuating said electrical switchbetween said positions at a rate which is a function of a measuredquantity;

at least one magnetic recording head for applying magnetic marks to arecording medium under the control of said electrical switch; and

means for supplying current to said magnetic recording head in adirection determined by the position of said electrical switch;

the improvement comprising flip-flop means electrically connectedbetween said electrical switch and said recording head for preventingmultiple magnetic marks from being applied by said recording head to therecording medium due to switch bounce.

6. The recording instrument of claim 5 wherein said means for supplyingcurrent is a constant current source.

7. The recording instrument of claim 5 further includingelectro-mechanical means connected to said flip-flop means to recordsaid changes in switch position simultaneously with the recording ofmagnetic marks on said recording medium.

* n: I: a m 5

1. In a recording instrument including: an electrical switch which canassume one of two positions; means for actuating said electrical switchbetween said positions at a rate which is a function of a measuredquantity; at least one magnetic recording head for applying magneticmarks to a recording medium under the control of said electrical switch;and means for supplying current to said magnetic recording head in adirection determined by the position of said electrical switch; theimprovement comprising: a pair of light emitting diodes connected ininverse parallel relation with each other and in series with each saidmagnetic recording head for indicating the existence of and thedirection of current flow through said recording head.
 2. The recordinginstrument of claim 1 further including flip-flop means electricallyconneCted between said electrical switch and said recording head forpreventing multiple marks from being applied by said recording head tothe recording medium due to switch bounce.
 3. The recording instrumentof claim 1 wherein a plurality of switches are provided to measure acorresponding plurality of measured quantities, wherein a plurality ofmagnetic recording heads are provided to apply magnetic marks to saidrecording medium, and wherein each of said switches is connected to acorresponding flip-flop to control recording current throughcorresponding said recording heads.
 4. The recording instrument of claim1 further including means for counting the changes in position of saidswitch means independently of the recording of magnetic marks on saidrecording medium.
 5. In a recording instrument including an electricalswitch which can assume one of two positions; means for actuating saidelectrical switch between said positions at a rate which is a functionof a measured quantity; at least one magnetic recording head forapplying magnetic marks to a recording medium under the control of saidelectrical switch; and means for supplying current to said magneticrecording head in a direction determined by the position of saidelectrical switch; the improvement comprising flip-flop meanselectrically connected between said electrical switch and said recordinghead for preventing multiple magnetic marks from being applied by saidrecording head to the recording medium due to switch bounce.
 6. Therecording instrument of claim 5 wherein said means for supplying currentis a constant current source.
 7. The recording instrument of claim 5further including electro-mechanical means connected to said flip-flopmeans to record said changes in switch position simultaneously with therecording of magnetic marks on said recording medium.